Customer networks are networks established by individuals or companies for internal communication. Customer networks may include local area networks (LAN) or wide area networks (WAN) that comprise a plurality of subscriber devices, such as personal computers, laptops, workstations, personal digital assistants (PDAs), wireless devices, network-ready appliances, file servers, print servers, or other devices. The customer networks may meet customer-specific needs using a number of different communication protocols, such as Asynchronous Transfer Mode (ATM) protocol, Ethernet protocol, Bridged Ethernet protocol, frame relay protocols, or other communication protocols. ATM and frame relay protocols, for example, are frequently used for transport of audio, video, and computer data between source and destination devices within a customer network. Such protocols may transfer information in fixed-length units, such as frames.
In order to allow remote customer networks to communicate, Internet Protocol (IP) based communication techniques are being developed that relay frames through an IP-based network, such as the Internet. According to the techniques, a network service provider of the IP network can receive frames from one of the customer networks, encapsulate the frames within packets, and route the packets through the IP network to another customer network.
Service provider networks include network devices, such as routers, that provide subscriber devices of the customer networks with access to the Internet or another network. For example, multiple subscriber devices may connect to a network switch, e.g., a digital subscriber line access multiplexer (DSLAM), maintained by the service provider network. Although data for the multiple subscriber devices connected to the network switch are transported over the same physical connection, each of the subscriber devices typically has a dedicated subscriber interface, e.g., an ATM virtual circuit (VC) or an Ethernet virtual local area network (VLAN), to the network device and hence the Internet.
VLANs are a generic grouping mechanism for Ethernet packets independent of media access control (MAC) addressing. VLANs enable the network switch to multiplex multiple protocol interfaces over a single physical Ethernet port. For example, the network switch may present both IP interfaces and Point-to-Point Protocol over Ethernet (PPPoE) interfaces on one or more VLANs. Typically, an Ethernet frame header includes a VLAN identification (VID) tag that identifies the VLAN associated with the Ethernet packet. The VLAN may comprise either a single tagged VLAN or a double tagged VLAN. A single tagged VID identifies the subscriber device that sent the packet to the network device. A double tagged VID identifies both the subscriber device that sent the packet and the network switch that transferred the packet from the subscriber device to the network device. Use of VIDs allows applications, such as a Broadband Remote Access Server (BRAS) application, to identify specific subscriber devices, thereby allowing these types of applications to provide subscriber specific services.
Currently, service provider networks are migrating away from ATM to Ethernet based infrastructures; however, many of these service providers are either functionally unable or refuse to include VIDs in Ethernet frame headers. Without VIDs, applications, such as a BRAS application, may no longer easily distinguish between multiple subscriber devices, which may significantly the limit ability to deliver subscriber specific services.